GNOME Bugzilla – Bug 708036
x264enc: Update documentation to specify default profile if no constraints are given
Last modified: 2013-09-24 08:48:27 UTC
When downstream does not set the profile field in the caps the first element in the profiles arrays is used. Since we want to default to 'main', it should be first in the list
Created attachment 254869 [details] [review] x264enc: really use 'main' as the default profile
Should it? I'd say that baseline should be the default as it should be supported by any h264 implementation. Also the order of the other profiles there is a bit weird, would be good to reorder that :)
I'd use baseline as default too, I was only trying to match the documentation :) http://cgit.freedesktop.org/gstreamer/gst-plugins-ugly/tree/ext/x264/gstx264enc.c#n40
I see, there are arguments for both I guess. With main as default you might in theory get better quality/compression-efficiency by default. Not sure what would be best here
The reason I put the highest first is that if you support high & main & baseline, you probably want the highest one first ? Otherwise you should restrict your downstream caps.
Created attachment 255157 [details] [review] x264enc: Update the documentation to match the default profile used
That makes sense, use the best possible quality unless you have restrictions. By default libx264 does not set any restriction: --------------- profile Default: not set Limit the profile of the output stream. If you specify a profile, it overrides all other settings, so if you use it, you will be guaranteed a compatible stream. If you set this option, you cannot use lossless encoding (--qp 0 or --crf 0). You should set this if you know your playback device only supports a certain profile. Most decoders support High profile, so there's no need to set this. Values available: baseline, main, high, high10, high422, high444. ----------------
That makes me think that their should be a value in the profile options when no restrictions applies at all (like for lossless encoding as described in the documentation)
commit 03a98eabce3b9f6f9e3111418d0c297522834d68 Author: Andoni Morales Alastruey <ylatuya@gmail.com> Date: Wed Sep 18 11:34:56 2013 +0200 x264enc: Update the documentation to match the default profile used https://bugzilla.gnome.org/show_bug.cgi?id=708036